描述 Description

The Littelfuse 235P is designed to protect 5-15 hp, 230 V, single-phase pumps from dry-well, dead-head, jammed impellers,

rapid-cycle, and overvoltage and undervoltage conditions. A calibration adjustment allows the 235P to be calibrated to your

specific pumping applications, reducing the possibility of false or nuisance tripping. A unique microcontroller-based voltage

and current-sensing circuit constantly monitors the incoming power for fluctuations causing overcurrent and undercurrent.

When an abnormality such as loss of suction is detected, the 235P deactivates its output relay and directly disconnects the

pump motor. The 235P communicates with a hand-held diagnostics tool called the Informer (sold separately). The Informer

displays parameters including calibration points, trip points, run time, and last faults. An external current transformer is

required for operation (sold separately).

Special considerations for pump cables larger than #10 AWG: In some cases where larger motors are installed with deepset

pumps, pump cables are used that exceed the relay’s terminal size. In these conditions, a short splice of #10 AWG or

#12 AWG may be a solution at the control box. Note: All local, state, and national electric codes should be followed when

applying this solution.

NOTE: The 235P model has a sensitivity adjustment for the dry-well trip point. After calibration is done, you can adjust the sensitivity for the dry-well/dead-head trip point from

70-90 of the full load. This makes the unit even more adaptable to varying pumping applications. If you have a very low producing well, increase the sensitivity closer to the 90

mark, or if you have a very heavy producing well, decrease the sensitivity around the 70 mark.

FEATURES BENEFITS

Proprietary microcontroller-based circuitry Constant monitoring of voltage and current for reliable pump

protection

Onboard sensitivity adjustment User-adjustable sensitivity knob makes the unit more adaptable to

varying pumping applications

Adjustable restart delay Allows user to select well recovery time delay after a dry-well

condition occurs, or to select manual reset

Built-in IR communications link When used with the Informer, allows user to see stored faults, run

time, and troubleshoot the pump while it’s running

LED indication Provides status and diagnostics for troubleshooting

Flexible reset Reset can be done through a push button on the relay or remotely with

optional 777-MRSW or OL-Reset remote reset kit